On your bike

Exercise regularly. Joints, and especially knees, dont like inactivity. Some types of exercise are particularly good for your knees for instance, cycling is better than running but the most important thing is to do something you enjoy, because thats the only way youll stick to any sort of exercise regime. So if running is the thing you love and nothing else will do, go for it. Alongside that, keep your weight under control, because the heavier you are, the more strain on your knees and of course exercise will help with that. Its also important to stick to a healthy diet not just as a weight-loss strategy, but because you need to give your joints the benefits of all the vitamins, minerals and other nutrients they need.